Process of evaporating solutions.



0. MANTIUS.

PROCESS OF EVAPOBATIBIG- SOLUTIONS.

APPLIOATION run) an. 2. 1908.

951,322; Patented Mar, 8, 1910.

' solutions in accordance iJNiE-FED dl r i lfldti PATEl-il @i l lt hl,

OTTO MANTIUS, 0F CHICAQG, ILLINOIS, ASSIGN OR TO ZAIREMBA COMPANY, OF

CHICAGO, ILLINOIS, A CORPORATION OF MAINE.

PROCESS OF EVAIORATING SOLUTIONS.

Specification of Letters Patent.

Application filed March 2, 1908.

To all whom it may concern:

Be it known that I, OTTO MaN'rIUs, a subject of the Emperor of Germany, and a resident of Chicago, in the county of Cook and tate of Illinois, have invented a certain new and improved Process of Evaporating Solutions, of'svhich the following is a specification.

This invention relates to an' improved process of evaporating solutions.

It is found in practice that,*w-here evaporation of solutions isefi'ected in closed evaporators, as standard types of vacuum pans, the liquor boils so rapidly that the separated salts have no time to form into large crystals. Heretofore when it has been desired to produce large crystals, this has been effected by boiling and concentrating the liquor in open tanks and then permitting it to cool gradually, or in open pans where the boiling is done very-slowly, as, for example, strike .pans used in sugar factories and grainers used in salt factories. This process is necessarily a slow and relatively expensive one and the production of large crystals in commercial quantities would necessitate the use of many of said strike pans or grains-rs.

The object of the present invention. is to provide a process for evaporating solutions,

whereby large crystals of the solid carried in solution may be produced in a closed evaporator and as a continuous operation.

To this end my improved process consists of the various steps hereinafter described and claimed.

For purposes of illustration, I have, in the drawing "forming part of the application, shown an evaporator especially designed and adapted for the evaporation of process, in which the figure is a side elevation of said evaporator. Referring to the drawing, A an evaporating pan or receptacle, and C a heater, allof which may be of any usual or approved construction, and which are connected in series by means of pipes l 2 and 3.

As shown, the pan type known as a vacuum vided'with a liquor supply pipe 4, which may be controlled either manually or automatically to maintain a substantially unipresents 13 a pump,

A is of the familiar pan, being pr0-' are continuous l l l l r l l l l l l i I 'the like, for maintaining a partial vacuum in the vapor space 6.

The interior of the evaporating pan A is divided into a plurality of coinmunicating chambers or compartments 8, 9, 10, 11 and 12, by means of transverse partitions l3, 1e 15 and 16, of which the partitions l3 and 15 from the bottom of said pan to apoint below the liquor level 5, prefer: ably about-"equal to the width of the succeeding compartment of the evaporator, the alternate partitions 1i and 16 extending above the liquor level 5 and terminating at sulhcient distance above the bottom of the evaporator to provide, for the accumulation of separated granular matter in the bottom of the evaporator and, at the same time, to insure a free passageway between adjacent compartments at the lower ends of said partitions about equal in size to the liquor passages defined by the upper ends of the partitions l3 and 15 and the liquor level 5. Said partitions 14 and 16 preferably terminate below the top of the panA, so that all of the compartments 8, 9, 10,11 and 12, above the liquor level 5, will be in open communication with the vapor 'space 6, thus providing for evaporation in all of said chambers, with consequent cooling and concentration of the liquor. This construction also provides for maintaining a com-' mon liquor level in all of ments.

The chamber said compartor compartment 8, which the liquor being'treated enters directly from with my improved the heater, is preferably considerably larger than the other chambers or compartments, being shown in the drawings as about twice the size. This relation, as also the number of said chambers or compartments, may be varied, as desired, to meet diii'ercnt conditions and requirements.

The admission pipe '1 preferably communicates with the first compartment- 8 adjacent to its lower end and the discharge pipe 2 with the last compartment 12 just below the liquor level, thus providing or the liquor traversing the entire length of each of said form liquor level, indicated by the dotted compartments in heater Q as separate from and ice side of the vacuum pa n A, my invention contemplates equally the use of heating means, as heatiogtubes, located. directly in the compartment 8, substantially a in the standard types of vacuum pans. .h this construction, the circulating pipe lW1ilCOI11- municatc directly with the discharge end of the pump 13.

lily improved process, which I Will now describe, inmlvcs on application of the prim ciple that Where supersaturated solutions in a. quiet state allowed to cool gradually, the solid matfer ried in solution Will be deposited in the f u of large crystals.

lo the practice of my improved process, a. steam press-mic, corresponding to a. desired initial tcmijaerutru'c, is maintained in the heater :2, es, for esample, 18 pounds absolute (3 pounds above atmospheric), correspending to a temperature of 222 degrees F, so that, allowing for radiation, the liquor enters the compartment. 8 of the vacuum pan ll hile l have, in the drawing, "h

A'at atempereture of about 221 degrees F. 1

Assuming that the pressure in the vapor space 3 8 pounds absolute pounds at mospherie), the boiling point of Water at the surface is 183 degrees and assuming that the solutio being treated saturated brine, the boiling point which is 6 per cent. higher than that of water, the boiling -.poi1itof the liquor at the surface 194.- (Llegrees ll. is, the liquor enters the. chamber 8 of the vacuum pen ll. a ternperature upproximutoly (logo 1*. shove the boiling point thereof at the su lCti. The liquor in said chamber will therefore boil, vigorously, with attendant rapid evaporation and cooling thereof, resulting in the supersetiu'otion of said liquor and the sec-- motion of the solid mutter (salt) held in solution in the form of small crystals.

From the compartment 53 the concentreted liquor passes successively through the compartments 9, l0, 11 end 12 at a 10W velocity or rate of speed, becoming gradually cooler from radiation end evaporation.

Thus, soon after leaving the compartment 8,

said liquor will tell to a. temperature below the boiling point or point. of ehullition and will bGCOl'I'lQ perfectly calm and quiet except for its slow current through the evaporator.

the solubility of most substances ins 1.1 the tompeiuturc and veins it results that, the temperature of the liquor falls during; its passage through the evaporator, clue to evaporation and radiation, the solid matter carried in solution will separate in the form of crystals, which beooo olarger and larger the lo gcr they are i comparth'icht to a point of supersaturetion, held in suspension, so that sale. crystals will become progressively larger in the various compartments from front to rear of the evaporator:

evaporating ouipertmeut 12 of the r liqi r enters the pipe Q; and passes to f pump, "which affords cooveuieut means .or regulating the velocity or flow of the current of liquor through the cvapora tor. in practice, in evaporating saturated oi-inc. I have obtained very satisfactory results "by operating the pumpet such a. speed to pred ce a current t r flow on? liquor in tl.1(- .cvepore.tor of about of an inch second. This speed can, l'lOWGVGl', be varied as it or desired. to produce larger or smaller 1 ,"stels and Will also very in trc 1t solutions.

Actual tests hero .luo'wh their whereas in uteri brine 1h standard types of eveporatore, the suit crystals or grains produced vary in size from. to

" inch square, by the practice of my improcess, with a. liquor current or ti of substantially of an inch per secou l, the sizes of the salt crystals or grains ueed vary from of an inch square in the first chamber, to about of an inch square in the lost chamber.

The or the crystals can he varied by increasing"- the number of compartments and by reducing the l'quor current or velocity in the or n oretor, either or both, if it is desired to produce larger crystals, or, by are dueing the number of compartments and increasing the liquor speed or velocity, either or both, if it dc .fcd to produce smaller crystals.

As thesolid matter held in solution. separates, it settles to the bottom of the evaporator, which, to provide for separating the different grades of salt produced in the different compartments of the evaporator, and

for conveniently discharging the same, compris hopper shaped sections 17', 18 and 19, the section 17 forming the bottom of the first compartment 8, the section 18 forming the bottom or" the compartments 9 and 10, and the sectlon 19 forming the bottom of the compartments 1]. and 12 and receiving the salt deposited in said compartments, respectively.

Any desired or approved means may be employed for removing the salt from the cvuporators. Said. means, however, are in no Way related to the present invention and need not, therefore, he described.

solution, which consists in passing a saturated liquor successively through. a series of cone unicating compartments at a low speed or velocity, boiling said liquor in the first point, their by to .orue calm and 4 2. The process of evaporating solutions to lefl'ect precipitation of the solids carried in solution, which consists in admitting the solution in u superheated condition to the first of 11 series of communicating compartments and passing said liquor successively i'lui'iugh said compartments at a low speed or velocity, permitting said liquor to boil in said first compartment to a point of supersaturation and to cool gradually in its passage through the other comparti'nents to a temperature below the boiling point, and thereby to become calm and quiet.

In testimony, that I claim the foregoing as my invention, 1 affix my signature in presence of two subscribing Witnesses, this 26th day of February, A. D. 1908.

OTTO M ANTI U S.

Witnesses CHARLES B. GILLSON K. A. Cos'r-ELLo. 

